The answer is not as easy as one might think. The National Center for State Court's Gavel to Gavel reports:
Florida HB 963 / SB 1458 (2012) Repeals existing state law permitting arbitration Trial Resolution Judges from wearing judicial robes. House Version: Approved by full House 3/5/12. Died in Senate Judiciary Committee. Senate version: Approved by Senate Judiciary Committee 1/25/12. Died in Senate Governmental Oversight and Accountability Committee.
Maine HB 32 (2012) Repeals language prohibiting magistrates of the Family Division of District Court from wearing black robes. Signed into law by Governor 3/17/11.
Oklahoma HB 1452 (2009) Requires creation of voter information pamphlets by State Election Board prior to elections. Prohibits candidates from using pictures in which they are wearing judicial robes. Died in House Rules Committee.
Wisconsin SB 383 (2010) Restructures states municipal court system. Revises existing law that "A municipal judge shall be properly attired in a robe or other suitable clothing when officially presiding in a municipal court" to read " A municipal judge shall wear a black robe while presiding in a municipal court except when exceptional circumstances exist." Signed into law by Governor 5/18/10.